Robust Superhydrophobic Material and Coating

Abstract

The invention provides a composition for forming a hydrophobic material, the composition being made by combining: a perfluorinated amine compound comprising at least two amine moieties, such as a compound made by combining a straight or branched chain C1-10 alkyl amine having at least two amine groups per molecule, with a straight or branched chain C1-12 perfluorinated carboxylic acid confining at least one —COOH group per molecule; an epoxy compound comprising at least two epoxy moieties; a lubricant, such as a perfluorinated polyether; a population of nanoparticles; and a solvent. Hydrophobic materials formed by evaporation of the solvent from such a composition are also provided as are intermediates excluding the lubricant which are used in the formation of such compositions. Such compositions are used in the formation of hydrophobic and particularly superhydrophobic surfaces. Advantageously these compositions are useful to form robust surface coatings that are resistant to mechanical wear.

1 . A composition for forming a hydrophobic material, the composition made by combining:
 a perfluorinated amine compound comprising at least two amine moieties;   an epoxy compound comprising at least two epoxy moieties;   a lubricant;   a population of nanoparticles; and   a solvent.   
     
     
         2 . A composition according to  claim 1 , wherein the epoxy compound is selected from bisphenol di- or poly- glycidyl ether compounds. 
     
     
         3 . A composition according to  claim 2 , wherein the epoxy compound is selected from bisphenol-A, bisphenol-AP, bisphenol-B, bisphenol-BP, bisphenol-C, bisphenol-E, bisphenol-F, bisphenol-G, bisphenol-M, bisphenol-P, or bisphenol-PH. 
     
     
         4 . A composition according to  claim 1 , wherein the perfluorinated amine compound is made by combining a straight or branched chain C 1-10  alkyl amine having at least two amine groups per molecule, with a straight or branched chain C 1-12  perfluorinated carboxylic acid containing at least one —COOH group per molecule. 
     
     
         5 . A composition according to  claim 4 , wherein the perfluorinated amine compound is made by combining an amine selected from diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and ethylenediamine; with a carboxylic acid selected from trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, heptafluoroisobutyric acid, nonafluorovaleric acid, nonafluoroisovaleric acid, nonafluoropivalic acid, difluoroacetic acid, 3,3,3-trifluoropropionic acid, 3,3,3-trifluoromethyl-2-trifluoromethylpropionic acid, (R,S)-5,7-difluorotryptophan hydrochloride, (R,S)-5,6,7-trifluorotryptophan hydrochloride, 2-amino-3-(4,5,6,7-tetrafluoro-1H-indol-3-yl)propionic acid hydrochloride, and (R,S)-4,5,6,7-tetrafluorotryptophan hydrochloride. 
     
     
         6 . A composition according to  claim 4 , wherein the amine and the perfluorinated carboxylic acid are combined to form the perfluorinated amine compound in an amine:carboxylic acid molar ratio in the range 1:0.75-1:2. 
     
     
         7 . A composition according to  claim 1 , wherein the lubricant is a perfluorinated polyether. 
     
     
         8 . A composition according to  claim 7 , wherein the perfluorinated polyether is a fluorocarbon ether polymer of polyhexafluoropropylene oxide having a chemical formula II:
   F—(CF(CF 3 )—CF 2 —O) n —CF 2 CF 3    (II),
   wherein n is in the range 10 to 60.   
     
     
         9 . A composition according to  claim 1 , wherein the nanoparticles in the population of nanoparticles are formed from material selected from TiO 2 , SiO 2 , ZnO, MnO, PTFE, CeO 2 , graphene, graphene oxide, carbon nanotubes, and carbon black. 
     
     
         10 . A composition according to  claim 1 , wherein the amount of nanoparticles included in the composition is below about 80 wt. % of the composition excluding solvent. 
     
     
         11 . A hydrophobic material formed by evaporation of solvent from a composition according to any one of the preceding claims, the hydrophobic material comprising:
 a cured perfluorinated epoxy resin;   the lubricant; and   the population of nanoparticles.   
     
     
         12 . An intermediate for forming a composition according to  claim 1 , wherein the intermediate is made by combining:
 the epoxy compound comprising at least two epoxy moieties;   the perfluorinated polyether;   the population of nanoparticles; and   the solvent.   
     
     
         13 . A kit comprising an intermediate according to  claim 12 , and a perfluorinated amine compound comprising at least two amine moieties. 
     
     
         14 . An article made from or coated with a composition according to  claim 1  or a hydrophobic material formed by evaporation of solvent from a composition according to any one of the preceding claims, the hydrophobic material comprising:
 a cured perfluorinated epoxy resin; 
 the lubricant; and 
 the population of nanoparticles. 
 
     
     
         15 . A method of applying a hydrophobic coating to an article, the method comprising applying a composition according to  claim 1  to the surface of the article, and heating the article and coating in air at between 80 and 120° C.